Amco Chemical

Bulletin Board

The public comment period for the Engineering Evaluation and Cost Analysis (EE/CA) will run from February 10- March 12, 2015. Comments should be addressed to Lynn Suer, 415-972-3148 or suer.lynn@epa.gov

Description and History

NPL Listing History

NPL Status: Currently on the Final NPL

Proposed Date: 04/30/03

Final Date: 09/29/03

Deleted Date:

In English and Spanish. En ingles y en español.SITE DESCRIPTION: The Former AMCO Chemical Facility (Facility) is located at 1414 3rd Street in Oakland, California, one block south of the West Oakland Bay Area Rapid Transit (BART) station. The Facility is bordered on the north by a vacant lot owned by BART, on the west by residences, on the south by 3rd Street, and on the east by Nelson Mandela Parkway (formerly Cypress Street). The size of the Facility property is approximately 160 - 200 feet by 226 feet (about 0.9 acre). The Cypress (I-880) Freeway corridor crosses just to the south, passing over 3rd Street near the southeast corner of the property. The current land use at the Facility is light industrial; land use in surrounding areas is a mix of commercial/light industrial and residential. The nearest residences are immediately adjacent to the Facility along 3rd and Center Streets.

OPERATIONAL HISTORY: Prior to the 1960s, the AMCO Chemical Site (Site) was used by a variety of businesses including an Anheuser Busch Store House (around 1911), a bottle and rag dealer (around 1931), and Walter Cole Tank Works (around 1951). From the 1960s to 1989, the Site was owned and operated by AMCO as a chemical distribution facility. Bulk chemicals were off-loaded from a rail spur onsite and stored in drums and storage tanks before being transferred to smaller containers for resale. Bulk chemical storage facilities included 12 aboveground tanks, two underground tanks, and numerous drums. The drums and tanks were removed from the Site in 1989. AMCO facility buildings that remain on the property include an office, a warehouse, and small storage sheds. Historical buildings that no longer exist at the Site include an ice house, formerly located on the north side of the property, and a large shed, formerly located at the western edge of the property. The warehouse was used to store drums and for the transfer of chemicals into smaller containers. The ice house was used for drum storage. From 1989 to 1998, DC Metals used the property, along with a few nearby properties on Center Street, as a scrap metals yard. DC Metals operations closed down in November 1998 and metal scrap was removed from the Site. The Site is currently leased to Cable Moore, Inc., and is used primarily for cable storage.

Contaminants and Risks

Contaminated Media

Groundwater

Air

Soil and Sludges

In 1996, investigations performed on behalf of PG&E and the California Department of Transportation documented the presence of chlorinated solventsand other contaminants such as vinyl chloridealong 3rd Street, south of the Site. Subsequent investigations confirmed the presence of chlorinated solvents and other contaminants, including vinyl chloride, in soil, soil gas, and groundwateron or near the Site. Some of these chlorinated solvents are human carcinogens. Sampling has indicated that the Site poses no immediate threat to residents; however, there is concern that contaminants from the Site may pose a potential threat if nothing is done. It is important to note that the groundwater beneath the Site is not being used by the community as a drinking water source.

Who is Involved

The Site is being addressed using federal funds. EPA is currently investigating parties that we believe may be responsible. Under the Superfund process, EPA may seek to have any identified PRPs to conduct some or all of the reponse actions at the Site and reimburse EPA for its costs. In some cases where EPA is unable to identify financially viable PRPs, EPA may continue to use federal funds to address contamination at the Site.

Investigation and Cleanup Activities

Initial Actions

EMERGENCY RESPONSE: Concern about environmental conditions at and near the Site arose in June 1995 when utility workers encountered strong chemical odors while digging in the area. Preliminary sampling at the Site and on 3rd Street, south of the Site, indicated the presence of vinyl chloride and other chlorinated solvents in soil, soil gas, and groundwater. We first became aware of the Site in 1996 when the California Department of Toxic Substances Control requested our assistance. We began a preliminary assessmentof the contamination by sampling soil gas at the Site and determined that a response to remove the contamination was necessary. Our Emergency Response Program (ERP)moved in quickly to set up a system to remove the contaminants from the groundwater and soil gas (vapors in the soil). In February 1997, we began operating a treatment system to remove vinyl chloride-contaminated groundwater and soil vapors. This treatment system was a dual-phase groundwater and vapor extraction system with a thermal oxidation treatment unit. The system operated until July 1998, when we turned it off in response to community concern over potential exposure to contaminants from the system’s exhaust stack. During the installation and operation of the treatment system, we were able to gain additional information about the source and nature of the contamination. Based on this information, we determined that the Site did not pose an immediate threat to the public, but did pose a potential long-term risk.
RESPUESTA DE EMERGENCIA (ERP, según sus siglas en inglés): Surgieron inquietudes sobre las condiciones medioambientales del sitio cuando unos trabajadores de una empresa de servicio público escarbaban por la zona y se encontraron con olores a fuertes químicos. Se tomaron muestras en el sitio por la calle Tercera, al sur del sitio y se determinó la presencia de cloruro de viniloy otros solventes de cloradosen el suelo, en el gas de sueloy en el agua subterránea. La primera vez que supimos del sitio fue en 1996 cuando el California Department of Toxic Substances Control (la agencia para el control de sustancias tóxicas) pidió nuestra ayuda. Comenzamos con una evaluación preliminarde la contaminación tomando muestras del gas de suelo del sitio y determinamos que era necesario tomar medidas para remover los contaminantes. Nuestro Programa de Respuesta de Emergencia (ERP, según sus siglas en inglés) rápidamente instaló un sistema para sacar los contaminantes del agua subterránea y gas de suelo (vapores en la tierra). En febrero de 1997, comenzamos la operación de un sistema de tratamientopara remover el cloruro de vinilo del agua subterránea y vapores de suelo. Este sistema de tratamiento es de doble fase para extracción de agua y tierra que consiste de una unidad de extracción con sistema para oxidación térmica. Este sistema operó hasta 1998, lo clausuramos por inquietudes de la comunidad sobre el potencial de contaminación por el tubo de escape. Durante la instalación del sistema de tratamiento pudimos entender un poco más sobre la raíz del problema y la razón de la contaminación. Con esta nueva información determinamos que el sitio no representaba una amenaza inmediata al público, pero que sí pudiera representar un riesgo a largo plazo.

Initial Actions

PRELIMINARY ASSESSMENT/SITE INVESTIGATION (PA/SI):
To verify that residents near the Site were not at risk from the contamination, we sampled the soil and groundwater at the Site, and the air from the crawlspaces of several adjacent homes. Sampling took place in December 1998, September 1999, and April 2000. High levels of vinyl chloride and other chemicals were found in soil and groundwater at and near the Site. In the September 1999 sampling, very low levels of vinyl chloride were found in crawlspace air at homes next to the Site, and in soil gas at one home. However, vinyl chloride was not found in the crawlspace or soil gas of the homes during previous or later sampling. Based on the available information, we do not believe that the very low levels of vinyl chloride found in 1999 could affect the health of people living in those homes. The findings of these investigations are summarized in detail in a Preliminary Assessment/Site Investigation (PA/SI)report, which can be found at the Site repositories. Additional sampling of groundwater, soil gas, and residential crawlspace air was conducted in August 2002 following the PA/SI. The results of this sampling event, which indicated no detectable levels of vinyl chloride in any of the two crawlspaces or four backyards where soil gas was sampled, are consistent with the results of the previous monitoring events. Sampling activities, referred to as Routine Site Monitoring, will be conducted periodically to verify that nearby residents are not being exposed to contamination. Based on the high levels of contamination in groundwater and soil at the Site, EPA Region 9 recommended in January 2001 that the Site be added to the National Priority List (NPL) of federal Superfundsites. On April 30, 2003 the proposal to list the AMCO Chemical Site on the NPL was published in the Federal Register. This marked the start of a 60-day period for public comment on the proposed listing. Since we did not receive significant objections to the proposed listing, the Site was officially added to the NPL on September 29, 2003.

Site Studies

REMEDIAL INVESTIGATION (RI): The draft report presents the findings of the Remedial Investigation (RI) that was performed at the AMCO Chemical Superfund Site (the Site) from September 2004 to November 2006. Field activities associated with the RI are ongoing, and this report will be updated to include data collected between November 2006 and the completion date of the feasibility study. The RI report will be finalized once the feasibility study is completed.

The purpose of the RI is to characterize the nature and extent of contamination at the Site, and to gather the data necessary for a baseline human health risk assessment (HHRA). The results of the RI and the HHRA will be used to support the feasibility study for the Site and, ultimately, the selection of any remedial actions.

The hydrogeology beneath the Site was studied as part of the RI to help evaluate the fate and transport of the site-related contaminants. The Site is underlain by two unconsolidated aquifers that are separated by a regional aquitard. The results of the RI indicate that groundwater contamination is limited to the upper aquifer. The upper aquifer is composed of fill and native sand and silty sand deposits with thin layers of silt and clay (Merritt Sand), and is approximately 55 to 70 feet thick. The Merritt Sand is underlain by a competent confining layer consisting primarily of lean clay (Older Bay Mud.) The Older Bay Mud is generally 50 to 90 feet thick in the vicinity of the Site. The lower aquifer (Alameda Formation) consists of variable fluvial and marine sediments. Its thickness below the site is unknown.

During the RI, the shallow water table fluctuated from approximately 2.5 to 6.5 feet below ground surface (bgs). In the dry season (May through October), flow generally appears to be toward the southwest; in the wet season (November through April), flow is generally to the south. Gradients are relatively flat in the vicinity of the Site, but are typically steeper north of 3rd Street, ranging from 0.006 to 0.008 feet per foot (ft/ft), and shallower south of 3rd Street, ranging from 0.001 to 0.003 ft/ft. Total dissolved solids (TDS) in groundwater south of 3rd Street generally exceed the Regional Water Quality Control Board’s Basin Plan criterion of 3,000 milligrams per liter (mg/L) for drinking water as a beneficial use.

To achieve the objectives of the RI, samples of light non-aqueous-phase liquid (LNAPL), groundwater, soil, soil gas, air, and produce were collected and analyzed in accordance with the 2004 Sampling and Analysis Plan (SAP) and subsequent modifications. Based on the history of the site and surrounding areas, samples of various media were collected from temporary and/or permanent locations both on and off the former AMCO facility, and were analyzed for some or all of the following: volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs), metals, pesticides, polychlorinated biphenyls (PCBs), dioxins/furans, cyanide, general chemistry, and physical parameters.

Over 200 individual contaminants were detected in groundwater, soil, soil gas, and air during the RI, with 98 of those identified as contaminants of concern (COCs). The COCs include VOCs (chlorinated and petroleum hydrocarbons), SVOCs, organochlorine pesticides, PCBs, metals, and dioxins/furans.

Key findings of the RI are as follows:

· Several feet of LNAPL were observed floating on groundwater beneath the central area of the former AMCO facility. The LNAPL consists primarily of VOCs, including tetrachloroethene (PCE) and trichloroethene (TCE), but also contains SVOCs, pesticides, and dioxins/furans. The LNAPL is serving as the primary continuing source of contamination to groundwater, soil, and soil gas.
· The highest concentrations of contaminants in groundwater and soil gas (primarily VOCs) were generally observed in the central and south-central areas of the former AMCO facility, corresponding with the known locations of former chemical storage units and buried distribution piping. However, other distinct areas of elevated contamination concentrations in groundwater and soil gas were observed beneath the large vacant lot on Center Street and beneath the UPRR/Amtrak yard south of the facility, suggesting that separate releases of contaminants have occurred in these areas.
· Groundwater contaminant concentrations beneath the central and south-central portions of the former facility decrease rapidly with depth. The concentrations in the deepest monitoring wells at the site are low or below detection levels, indicating that dense non-aqueous-phase liquid (DNAPL) has not migrated below approximately 20 to 30 feet bgs at the site.
· The VOCs identified as key contaminants (chlorinated solvents and petroleum hydrocarbons) are undergoing significant biodegradation in groundwater. However, data suggests that the down gradient edge of the VOC plume is expanding despite the naturally occurring biodegradation.
· 1,4-Dioxane, a highly mobile and recalcitrant contaminant, has widely migrated in groundwater from the site, and it is expected to continue migrating. Other contaminants mobilized in groundwater are soluble arsenic, iron, and manganese. Other metals, organochlorine pesticides, PCBs, and dioxins/furans generally have limited mobility in the environment, and the extents of these compounds are limited to the immediate vicinities of their historic suspected source areas.
· The lateral extent of groundwater contamination in the mid and deeper zones has not been fully delineated to the current screening levels.
· Several contaminants in groundwater currently exceed risk criteria for the ingestion pathway; however, groundwater is not currently used nor is it likely to be used in the future as a source of drinking water.
· The distributions of contaminants in soil are less centralized and more widespread than in groundwater, suggesting multiple industrial, non-industrial, and non-point sources. Many contaminants in soil, particularly lead, exceed risk criteria for industrial and residential receptors.
· Elevated lead concentrations were detected at several residential properties adjacent to or near the former AMCO facility. The concentrations of lead detected in the soil posed an immediate risk to residents, particularly children. A soil removal action to address the lead contamination was performed at all residential parcels occupying the same block as the former AMCO facility.
· Several VOCs were detected above screening levels, but within the acceptable risk range in residential soil gas, crawlspace air, and ambient air. No VOC detections exceeded acute reference concentrations, indicating that there is no immediate health threat to residents. The primary source of the VOCs in residential soil gas and air is groundwater, not soil.
· At the former AMCO facility and off-facility locations, the concentrations of several contaminants in soil, soil gas, and groundwater would pose an unacceptable risk to site workers. However, the current concrete pavement at the former AMCO facility and off-facility locations provides a protective layer that isolates workers from the contaminated soil, soil gas, and groundwater underneath.
· Several VOCs were detected above screening levels, but within the acceptable risk range in crawlspace air samples collected from the facility office. No VOC detections exceeded acute reference concentrations, indicating that there is no immediate health threat to workers.
· Concentrations of metals and VOCs in sampled homegrown produce are below levels of concern for ingestion.

Cleanup Results to Date

Potentially Responsible Parties

Potentially responsible parties (PRPs) refers to companies that are potentially responsible for generating, transporting, or disposing of the hazardous waste found at the site.

EPA is currently investigating parties that we believe may be responsible. Under the Superfund process, EPA may seek to have any identified PRPs to conduct some or all of the response actions at the Site and reimburse EPA for its costs. In some cases where EPA is unable to identify financially viable PRPs, EPA may continue to use federal funds to address contamination at the Site.

Documents and Reports

Community Involvement

Public Meetings:EPA is accepting Public Comments on the EE/CA Document, posted above, until March 12, 2015. Please contact Community Involvement Coordinator Sarah Cafasso (info below) for more information or Brian Beverage, CAG Co-Chair, for information about the CAG.